Foreign Key Error script Generation

Question

here is
CREATE table script
create table employee_history
(empl_id_hist number,
empl_name varchar2(20)
alter table employee_history
add constraint emp_TO_empHIST foreign key (empl_id_hist)
references employee (empl_id);
Create table employee
(empl_id number,
ename varchar2(20));
some empl_id_hist values not in Master table employee.
now Foreign Key disabled.
for checking not valid empl_id_hist ids
I am trying to generate a script like this using Dynamic SQL.
select unique empl_id_hist from employee_history
where empl_id_hist not in (select empl_id from employee);
but i am getting same Column empl_id_hist (instead of empl_id ) in Subquery too
i.e
select unique EMPL_ID_HIST from employee_history
where EMPL_ID_HIST not in (select EMPL_ID_HIST from employee);
DECLARE
CNT NUMBER := 0;
V_SQL_STR VARCHAR2(255);
v_col_name VARCHAR2(255);
v_ind CHAR(1);
v_sql_where VARCHAR2(255);
CURSOR C1 IS
SELECT DECODE(c.position, 1, b.table_name, ' ') MASTER_TAB,
DECODE(c.position, 1, a.table_name, ' ') CHILD_TAB,
DECODE(c.position, 1, a.constraint_name, ' ') constraint_name,
c.column_name colname
from dba_constraints a,dba_constraints b, dba_cons_columns c
where a.status = 'DISABLED'
AND a.constraint_type = 'R'
AND a.constraint_name = c.constraint_name
and a.r_constraint_name = b.constraint_name (+)
order by b.table_name, a.table_name, c.position;
CURSOR c2(cons_name VARCHAR2) IS
SELECT column_name FROM User_Cons_Columns
WHERE constraint_name = cons_name
ORDER BY column_name;
BEGIN
FOR R1 IN C1 LOOP
v_col_name := '';
BEGIN
FOR r2 IN c2(r1.constraint_name) LOOP
cnt := cnt + 1;
IF cnt <= 1 THEN
V_ind := 'y';
V_SQL_sTR := 'SELECT UNIQUE A.'||R1.colname ||' FROM ' ||R1.CHILD_TAB ||' A' || chr(10);
V_SQL_STR := V_SQL_STR ||'WHERE A.'||R1.colname ||' NOT IN ';
V_SQL_STR := V_SQL_STR || '(SELECT B.'|| R1.colname ||' FROM ' || R1.MASTER_TAB ||' B);' ||chr(10);
V_COL_NAME := V_COL_NAME || R2.COLUMN_NAME ||',';
v_Sql_where := 'WHERE A.'||R2.COLUMN_NAME ||' = B.' || R2.COLUMN_NAME ||chr(10);
ELSE
v_ind := 'n';
v_Sql_where := v_Sql_where || 'AND A.'||R2.COLUMN_NAME ||' = B.' || R2.COLUMN_NAME ||chr(10);
V_COL_NAME := V_COL_NAME || R2.COLUMN_NAME ||',';
END IF;
END LOOP;
v_sql_where := v_sql_where ||');';
cnt := 0;
END;
IF v_ind = 'y' THEN
DBMS_OUTPUT.PUT_LINE(V_SQL_sTR);
ELSIF v_ind = 'n' THEN
v_sql_str := '';
v_col_name := SUBSTR(v_col_name,1,LENGTH(v_col_name) - 1) || '';
V_SQL_STR := 'SELECT UNIQUE '|| V_COL_NAME ;
V_SQL_STR := V_SQL_STR || ' FROM ' || R1.CHILD_TAB || ' A'|| CHR(10);
V_SQL_STR := V_SQL_STR || 'WHERE NOT EXISTS ( '||CHR(10);
V_SQL_STR := V_SQL_STR || 'SELECT 1 FROM ' ||R1.MASTER_TAB ||' B';
DBMS_OUTPUT.PUT_LINE(V_SQL_STR);
DBMS_OUTPUT.PUT_LINE(V_SQL_WHERE);
DBMS_OUTPUT.PUT_LINE('');
END IF;
v_ind := '';
END LOOP;
END;
thanks in advance

Answer 1

That's because with this cursor
CURSOR c2(cons_name VARCHAR2) IS
SELECT column_name FROM User_Cons_Columns
WHERE constraint_name = cons_name
ORDER BY column_name;You assume that the column names are the same in both tables. You will need to read from user_cons_columns twice, once with the fk constraint name, once with the pk constraint name.
SQL> create table parent (id number constraint parent_pk primary key) ;
Table cr&eacute;&eacute;e.
SQL> create table child (child_id number,
  2                      constraint child_fk1 foreign key (child_id)
  3                      references parent (id)
  4                     ) ;
Table cr&eacute;&eacute;e.
SQL> select
  2     a.column_name as parent_column_name,
  3     b.column_name as child_column_name
  4   from
  5     user_cons_columns a, user_cons_columns b
  6   where
  7     a.constraint_name = 'PARENT_PK'
  8     and b.constraint_name = 'CHILD_FK1'
  9     and a.position = b.position
10   order by
11     a.position ;
PARENT_COLUMN_NAME             CHILD_COLUMN_NAME
ID                             CHILD_ID